涅槃經遊意 1.55

1.55

解云：病藥無常者，以無常治常，常病既去，無常之藥亦除。如三修耶，常雖去猶存無常，故成尤疾。所以文云王今病重故也。此一向須寫寫矣。

An explanation says: As for the impermanence of illness and medicine, one treats permanence with impermanence; once the illness of permanence is gone, the medicine of impermanence is also eliminated. Like the three cultivations, though permanence is gone, impermanence still remains, which therefore becomes a severe illness. This is why the text says the king is now severely ill. This must be purgated entirely.